JP2010165270A - Continuously-arranged sensor system, network unit, and sensor unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To recognize the change of the parameter of each sensor unit without increasing communication traffic in a continuously-arranged sensor system. <P>SOLUTION: The continuously-arranged sensor system is configured of a network 10 and a plurality of sensor units 30-1 to 30-16, and they are connected through a serial transmission line 41. When a parameter such as a threshold is changed by each sensor unit, an update flag of the parameter is set, and the update flag is transferred through the serial transmission line 41 to the network unit 10 during normal data transfer. Only when the update flag is set, the network unit 10 requests the sensor unit to transmit the parameter. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a continuous sensor system that monitors the state of an object to be detected, a network unit used in the sensor system, and a sensor unit.

  In an automated production line, production is performed while monitoring the machining state of the workpiece in order to reliably machine the workpiece. Therefore, in an automated production line, a number of sensors for monitoring the machining state are arranged in the vicinity of the workpiece (object to be detected), and the workpiece is machined while monitoring the discrimination signal of each sensor.

  In such a sensor system, since wiring between a large number of sensors and sensor control devices is troublesome, these devices are unitized and each unit is physically connected to connect each unit. A continuous sensor system that simultaneously completes wiring between the two is utilized. In a continuous sensor system, a large number of sensor units are installed in the vicinity of the workpiece, and a large number of sensor heads such as optical fibers connected to each sensor unit are placed in the vicinity of the monitoring portion of the workpiece. In addition, a continuous sensor system is known in which a detection signal output from each sensor unit is monitored by a host controller via a network unit.

  Patent Document 1 discloses a sensor system having two transmission paths by parallel transmission and serial transmission as a measure for transmitting a sensor discrimination signal from each sensor unit to a network unit in real time and transmitting other sensor information. Is described.

  According to this configuration, the sensor detection signal of each sensor unit is independently transmitted to the network unit side through the parallel transmission path, so that the sensor detection signal can be transmitted to the network unit side without delay, and work can be performed at high speed. Can be done. Various sensor information such as the amount of light received by the sensor and threshold value is transmitted as digital data to the network unit and centrally managed by the host controller, or command signals are transmitted from the host controller and network unit to each sensor unit. Thus, it is possible to perform centralized control that controls the light emission timing of the sensor head of each sensor unit and changes the setting.

  Patent Document 2 proposes a sensor system in which a plurality of sensor amplifiers and a sensor amplifier management device are connected by data communication.

JP 2004-295276 A Japanese Patent Laid-Open No. 2003-97983

  However, a threshold value, a use distance, and the like for determining a normal physical quantity and converting it into a binary signal are set in the sensor unit. Among the continuous sensor systems, there is a system in which a higher-order network unit sets parameters such as a threshold value for each sensor unit, and the sensor unit cannot set parameters independently. On the other hand, there is also a continuous sensor unit in which an operation unit is provided in each sensor unit, and a threshold value, a use distance, and the like can be set independently. In the case of the latter sensor unit, the network unit inquires of each sensor unit about the setting parameter, and it is necessary to hold the setting parameter in the network unit in case a transfer request is received from the host controller.

  In the continuous sensor system, the network unit periodically sends a data transfer command for requesting transfer of a physical quantity such as a determination signal or a received light amount to each sensor unit, and collects data from each sensor unit. Since data such as discrimination signals and physical quantities change frequently, it is necessary to collect them at high speed. On the other hand, parameters such as threshold values are not changed frequently, so if you mix and communicate with data that needs to be collected at high speed, the cycle of collecting data that needs to be collected at high speed may become longer. There was a problem.

  The present invention has been made paying attention to such a problem, and it is possible to hold parameters that may be independently changed in each sensor unit in the network unit, and it takes time for processing. It is an object of the present invention to provide a continuous sensor system that can be held without any problem, and a network unit and a sensor unit used in the sensor system.

  In order to solve this problem, a continuous sensor system of the present invention includes a network unit connected to a host controller and at least one sensor unit, and the network unit, any one of the sensor units, and the A continuous sensor system configured by connecting sensor units, wherein each sensor unit outputs a detection signal corresponding to a physical quantity detected from a detection target, and for determination by the determination unit An operation unit for setting a parameter including a threshold value, a parameter memory for holding a parameter set by the operation unit, an update flag indicating whether the parameter is updated, and a detection signal obtained from the sensor unit as a threshold value. And an update flag is set when the parameter is updated from the operation unit. A control unit that simultaneously transmits an update flag to the network unit when sending at least one of a determination signal and a detection signal of the sensor unit, a connection unit that connects to either the adjacent network unit or sensor unit, and a plurality of bits Serial transmission means for transmitting and receiving a serial signal formed by the above-mentioned signal, and the network unit includes a connection means for connecting to any one of the adjacent sensor units, and a discrimination signal for the sensor unit. Serial transmission means for serially transmitting and receiving serial signals formed of a plurality of bits, a parameter memory for holding parameters of each sensor unit, and updating of parameters among data received via the serial communication means When flagged, the update flag A control unit for requesting transmission of the modified parameters to the sensor unit sends a grayed was erected data, and having a.

  Here, the control unit of the network unit may collect the parameters set in the sensor units when the power is turned on and store the collected parameters in the parameter memory.

  Here, each sensor unit may have a parallel signal line for transmitting the discrimination signal output from the control unit to the network unit in parallel.

  Here, the network unit has a table memory for holding a discrimination signal sent from each sensor unit, and the control unit of the network unit outputs the discrimination signal generated by the control unit of the sensor unit as a parallel signal. The table memory may be updated by detection based on a line signal change.

  In order to solve this problem, a network unit of the present invention includes a network unit connected to a host control device and at least one sensor unit, and the network unit and any one of the sensor units and the sensor units. A network unit used in a continuous sensor system configured by connecting a plurality of bits, including connection means for connecting to any one of the adjacent sensor units, and a discrimination signal of the sensor unit, Serial transmission means for transmitting and receiving serial signals to be formed serially, a parameter memory for holding parameters of each sensor unit, and a parameter update flag among data received via the serial communication means are set Sometimes data that is flagged for update A control unit for requesting transmission of the changed parameters for delivery sensor units, those having a.

  In order to solve this problem, a sensor unit of the present invention includes a network unit connected to a host control device and at least one sensor unit, and the network unit and any one of the sensor units and the sensor units. Is a sensor unit used in a continuous sensor system configured by connecting a sensor unit, including a sensor unit that outputs a detection signal corresponding to a physical quantity detected from a detection target, and a threshold value for discrimination by the discrimination unit An operation unit that sets parameters, a parameter memory that holds parameters set by the operation unit, and an update flag that indicates whether the parameters are updated, and a detection signal obtained from the sensor unit are determined according to a threshold value In addition, when a parameter is updated from the operation unit, an update flag is set and A control unit that simultaneously transmits an update flag to the network unit when transmitting at least one of a signal and a detection signal of the sensor unit, a connection unit that connects to either the adjacent network unit or the sensor unit, and a plurality of bits Serial transmission means for transmitting and receiving a serial signal formed by the signal.

  Here, the discrimination signal in the present invention refers to a binarized signal obtained by comparing a signal based on the detection signal of the sensor with a predetermined threshold value. The parameter includes a threshold value for binarizing the detection signal. In addition to this, the usable distance of the sensor unit, threshold hysteresis, output mode, and the like may be included in the parameters.

  In the continuous sensor system according to the present invention, each sensor unit transmits an update flag at the same time as transferring data such as a discrimination signal and a physical quantity. Therefore, the network unit can request transmission of the updated parameter only to the sensor unit for which the update flag is set. The network unit can centrally manage the parameters of each sensor unit with a minimum increase in traffic.

  As the sensor unit of the present invention, a transmissive or reflective photoelectric sensor unit is conceivable. In the case of a photoelectric sensor, a fiber sensor or a sensor unit that projects an optical fiber from the sensor unit to an object detection region is used. A separation photoelectric sensor in which a head incorporating an optical element such as a light receiving element is connected by an electric cable is suitable. Since the fiber sensor and the separation photoelectric sensor can be used alone without being connected to each other, it is preferable that one sensor unit has one or two sensor heads. The sensor unit may be another type of sensor unit such as a proximity sensor, a pressure sensor, or an ultrasonic sensor, but even in this case, there is a separation sensor in which the detection unit and the sensor unit are connected by an electric cable. Is preferred.

  In the present invention, the connection means for connecting adjacent units includes a connection means for physically connecting the units and a signal connection means for performing signal transmission. As signal connection means for performing signal transmission, connection means for performing signal transmission by electrical connection or connection means for performing signal transmission by transmitting and receiving light can be employed.

  In the continuous sensor system, the parallel transmission line can be formed by a pair of connectors in which the same number of connection terminals are arranged in each sensor unit. In this case, each connection terminal of the upstream connector and each connection terminal of the downstream connector are associated with each other, and the sensor determination signal is given to one of the connection terminals arranged on the upstream side, and the downstream side. Each of the connection terminals on the side can be connected to the connection terminals on the upstream side excluding the connection terminals to which the determination signal is connected, by sequentially shifting the correspondence based on a predetermined rule, thereby forming a parallel transmission line.

  In the continuous sensor system according to the first to fourth aspects of the present invention, when the parameter of the sensor unit is updated, the parameter of the sensor unit updated through the serial transmission means is transmitted to the network unit with the minimum increase in communication traffic. Can be transferred. The parameter is temporarily held in the parameter memory and can be transferred to the host control device in response to a request from the host control device. Thereby, it is possible to provide a continuous sensor system capable of centrally managing the operation state of each sensor unit on the host controller side.

  According to the third, fourth, seventh, and eighth aspects of the invention, the sensor discrimination signals output from each sensor unit are transmitted to the network unit via the parallel transmission line independently of each other without delaying, and the network. The unit can determine the state of the object to be detected with reference to the transmitted determination signal of each sensor unit.

  According to the second and sixth aspects of the invention, since the parameters of each sensor unit are collected when the power is turned on, high-speed data collection is possible thereafter.

  According to invention of Claims 5-8, the network unit which can be used conveniently for this continuous sensor system can be provided.

  According to invention of Claim 9, the sensor unit which can be used conveniently for this continuous type sensor system can be provided.

FIG. 1 is an overall configuration diagram of a continuous sensor system according to a first embodiment of the present invention. FIG. 2 is a block diagram of the network unit according to the first embodiment. FIG. 3A is a perspective view of the network unit according to the first embodiment viewed from one side, and FIG. 3B is a perspective of the network unit of FIG. 3A viewed from the opposite side. FIG. FIG. 4A is a diagram showing an example of a table memory according to the first embodiment of the present invention. FIG. 4B is a diagram showing an example of a parameter memory according to the first embodiment of the present invention. FIG. 5 is a block diagram of the sensor unit according to the first embodiment. FIG. 6A is a perspective view of the sensor unit according to the first embodiment of the present invention viewed from one side surface, and FIG. 6B is a side view of the sensor unit of FIG. FIG. FIG. 7 is a perspective view showing the overall configuration of the continuous sensor system according to each embodiment of the present invention. FIG. 8 is a flowchart showing the operation of the network unit according to the first embodiment of the present invention. FIG. 9 is a diagram showing a communication sequence of the continuous sensor system according to the first embodiment of the present invention. FIG. 10 is a diagram showing a sequence of sensor units of the continuous sensor system according to the first embodiment of the present invention. FIG. 11 is an overall configuration diagram of a continuous sensor system according to a second embodiment of the present invention. FIG. 12 is a block diagram showing the configuration of the network unit of the continuous sensor system according to the second embodiment of the present invention. FIG. 13 is a block diagram showing the configuration of the sensor unit of the continuous sensor system according to the second embodiment of the present invention.

(First embodiment)
FIG. 1 is a diagram showing an overall configuration of a continuous sensor system according to a first embodiment of the present invention. The continuous sensor system 1 is configured by connecting at least one, here 16 sensor units 30-1 to 30-16 to a network unit 10 in series. These units are electrically connected by a serial transmission line 41 composed of at least two lines. Hereinafter, the direction toward the network unit 10 is referred to as an upstream direction, and the direction toward the sensor unit 30-16 is referred to as a downstream direction. The network unit 10 has a function of transmitting necessary signals to the host controller 42 while aggregating signals transmitted from the sensor units 30-1 to 30-16. They are connected via a bus 43.

  Next, each unit will be described in detail. FIG. 2 is a block diagram showing the internal configuration of the network unit 10, and FIGS. 3A and 3B are perspective views showing the network unit 10 from different directions.

  As shown in FIG. 2, the network unit 10 is configured to include an upper interface (IF) 11 a and a serial communication unit 11 b in the control unit 11. In addition, a display unit 12, an operation unit 13, a table memory 14, a parameter memory 15, and connectors 16, 17, and 18 are connected to the control unit 11 of the network unit 10.

  The control unit 11 has a function of transmitting / receiving a serial signal to / from the sensor unit via the serial transmission line 41.

  The host interface 11 a is an interface for receiving a command from the host controller 42 via the connector 18 and transferring the held data to the host controller 42.

  The serial communication unit 11b is connected to the serial transmission line 41 of the connector 16, and performs serial communication with each sensor unit connected to the continuous sensor system, and constitutes a serial transmission means.

  The table memory 14 is a memory that holds discrimination signals (on / off signals) and sensor information of a large number of sensor units connected to the network unit 10 as a table, and is configured by a volatile memory. As shown in FIG. 4A, the table memory 14 has a first area 14-1 and a second area 14-2. Here, the sensor units 30-1 to 30-16 are denoted by # 1 to # 16. The first area 14-1 is an area for holding a discrimination signal transmitted from the serial transmission line 41. The second area 14-2 is an area for holding sensor information of each sensor unit transmitted through the serial transmission line 41. The sensor information is, for example, the amount of received light when the sensor unit is a photoelectric sensor.

  As shown in FIG. 4B, the parameter memory 15 is a memory for holding parameters set in a large number of sensor units 30-1 to 30-16 connected to the network unit 10, and is constituted by a volatile memory. The

  The connector 16 includes five connection terminals, of which the connection terminals 16 a and 16 b are terminals connected to the serial transmission line 41. The connection terminal 16c is a connection terminal for timing signals. The connection terminals 16d and 16e are terminals for supplying power and are connected to a connector 17 for supplying power.

  The connector 16 of the network unit 10 constitutes an electrical connection means with the sensor unit 30-1, and transmits / receives a serial signal via the serial transmission line 41 and transmits a timing signal, It also has the function of supplying power to the sensor unit.

  The network unit 10 is a unit in which members are housed in a rectangular parallelepiped case 21 as shown in FIGS. 3A and 3B, and is used by connecting one sensor unit to the side wall thereof.

  As shown in FIG. 3A, the connector 18 is provided on the upper surface of the case 21. The connector 18 is a connector for connecting a host controller 42 such as a programmable controller or a computer. One end of the case 21 in the longitudinal direction is provided with a connector 17 composed of a screw-type terminal for connecting a power supply line (not shown). In addition, operation switches of the display unit 12 and the operation unit 13 are provided on the upper surface of the case 21.

  As shown in FIG. 3B, the connector 16 described above is provided on one side surface of the case 21. The connector 16 has five connection terminals, two of which are connected to the downstream serial transmission line 41, and the rest are connection terminals for timing and power.

  Engagement recesses 22a and 22b are provided on one side surface of the case 21 in proximity to both ends in the longitudinal direction. The engaging recesses 22a and 22b are engaged by engaging engagement protrusions provided in a sensor unit 30-1 described later, and are physical connection means for positioning and connecting the units to each other. Is configured.

  Next, the sensor unit will be described. In the present embodiment, 16 sensor units 30-1 to 30-16 are connected. However, since each sensor unit has the same configuration, the sensor unit 30-1 will be described with reference to the drawings. FIG. 5 is a block diagram showing an internal configuration of the sensor unit 30-1. 6A is a perspective view of the sensor unit 30-1 as viewed from one side surface, and FIG. 6B is a perspective view of the sensor unit 30-1 as viewed from the opposite side surface. . The sensor unit 30-1 of the present embodiment is a photoelectric sensor having a pair of light projecting and light receiving optical fibers as a sensor head, and generates a detection signal corresponding to the amount of light received by the light receiving optical fiber. It has a function of outputting a discrimination signal obtained by binarizing the detection signal with a predetermined threshold.

  As shown in FIG. 5, the sensor unit 30-1 has a control unit 31 formed using a one-chip gate array G or a microprocessor. The control unit 31 includes a timing control unit 31a, a determination unit 31b, and a serial communication unit 31c. The control unit 31 is connected with a light emitting unit 32, a light receiving unit 33, a display unit 34, an operation unit 35, a parameter memory 36, an output transistor Q1, and connectors 37 and 38.

  The control unit 31 has a function of transmitting and receiving serial signals to and from the network unit 10 via the serial transmission line 41. Further, as will be described later, it has a function of turning on an update flag in the parameter memory 36 when a parameter in the sensor unit 30-1 is updated and resetting the flag when the parameter transmission is completed.

  The timing control unit 31a gives a timing signal to the light emitting unit 32 when a timing signal is transmitted to the connection terminal 37c, and outputs a timing signal to the connection terminal 38c after a predetermined time, for example, about 10 μs elapses. .

  The determination unit 31b is a determination unit that discriminates the amount of received light according to a predetermined threshold value and converts it into a determination signal that is binarized on / off. The sensor discrimination signal is directly output to the outside via the output transistor Q1 and the output line 39.

  The serial communication unit 31c is connected to the serial transmission line 41 of the connectors 37 and 38, and performs serial communication with the network unit 10 connected to the continuous sensor system, and constitutes a serial transmission means.

  The light emitting unit 32 drives the light emitting element based on the timing signal from the timing control unit 31a. Light from the light emitting element is transmitted through the optical fiber 32a and radiates light from the tip. The light radiated from the optical fiber 32 a enters the optical fiber 33 a through the object detection region and is guided to the light receiving unit 33. The light receiving unit 33 converts incident light into an electric signal and amplifies it.

  Here, the light emitting unit 32, the light receiving unit 33, and the optical fibers 32a and 33a constitute a sensor unit that outputs a detection signal in accordance with a physical quantity detected from a detection target.

  The parameter memory 36 is a memory that holds parameters such as threshold values set individually in each sensor unit and parameters set from the network unit, and is configured by a nonvolatile memory. The parameter memory 36 is provided with an update flag area that is set when a parameter is updated.

  The connector 37 is formed of a connector having the same shape as the connector 16 of the network unit 10 and the connector 38 of the adjacent sensor unit, and can be connected to each other. The connector 37 includes two connection terminals 37a and 37b connected to the upstream side of the serial transmission line 41, a connection terminal 37c for timing signals, and connection terminals 37d and 37e for power supply.

  The connector 38 has two connection terminals 38 a and 38 b connected to the downstream side of the serial transmission line 41. A serial transmission line 41 is formed by directly connecting the connection terminals 37 a and 37 b of the connector 37 and the connection terminals 38 a and 38 b of the connector 38.

  The connection terminal 37c of the connector 37 is connected to the connection terminal 38c of the connector 38 via the timing control unit 31a. The connection terminals 37d and 37e of the connector 37 and the connection terminals 38d and 38e of the connector 38 are directly connected to supply power to the inside of the sensor unit 30-1 and supply power to the downstream sensor unit. To do.

  As shown in FIGS. 6A and 6B, the sensor unit 30-1 is a unit in which a member is accommodated in a case 51 having a narrow width. On the upper surface of the case 51, a display unit 34 formed of a four-digit 7-segment LED display and an operation unit 35 including various switches are provided. The display unit 34 can simultaneously digitally display the received light amount of the sensor and the set threshold value, and the received light amount and margin.

  A detachable cover that covers the entire upper surface is provided on the upper portion of the case 51, but is omitted in FIG. Further, head mounting holes 52a and 52b for mounting the optical fibers 32a and 33a and fixing levers for fixing the optical fibers 32a and 33a are provided at the longitudinal ends of the case 51.

  As shown in FIG. 6A, a connector 37 is provided on one side surface of the case 51. Further, on one side surface of the case 51, engagement protrusions 53a and 53b are provided close to both ends in the longitudinal direction. The engagement protrusions 53a and 53b are engaged with the engagement recesses 22a and 22b of the network unit 10 and constitute physical connection means for positioning and connection in connection with the network unit. ing. The connector 37 constitutes connection means for electrically connecting to the upstream network unit 10 or sensor unit.

  As shown in FIG. 6B, a connector 38 is provided on the other side surface of the case 51 at a position symmetrical to the connector 37. Further, on the other side surface of the case 51, engagement concave portions 54a and 54b are provided in proximity to both ends in the longitudinal direction. The engagement recesses 54a and 54b are engaged by engaging engagement protrusions provided on the downstream sensor unit, and constitute physical connection means for positioning and connection when the sensor units are connected to each other. is doing. The connector 38 constitutes connection means for electrically connecting to the downstream sensor unit.

  In addition to the detection operation, the sensor unit 30-1 of the present embodiment is capable of switching display data, setting parameters, and switching operation states by the display unit 34 by operating each switch of the operation unit 35. For example, an object can be placed at a desired position in the detection region, and a threshold value can be set so that the object is turned on at that position, or a threshold value hysteresis can be set. Further, since the usable distance is changed, the drive level of the light emitting element of the light emitting unit 32 can be set. In addition, it is possible to switch the output mode for outputting the ON signal when the light enters the light receiving unit 33 or when the light is blocked. The threshold value set in this way, the drive level of the light emitting unit, and the like are collectively referred to as parameters. A set of set parameters is held in the parameter memory 36. The display data of the display unit 34 can be changed or the operation mode can be switched based on a command transmitted via the serial transmission line 41.

  Next, the configuration and operation of the continuous sensor system 1 formed by combining the network unit and the sensor unit will be described. The continuous sensor system 1 according to the present embodiment can be variously formed by combining the network unit 10 and at least one sensor unit. Here, as shown in FIGS. 1 and 7, one network unit 10 is used. And 16 sensor units 30-1 (# 1) to 30-16 (# 16) are connected to each other. The connector 16 and the connector 37 are connected by connecting the network unit 10 and the sensor unit 30-1. The connector 38 of each sensor unit and the connector 37 of the adjacent sensor unit are connected.

  In the continuous sensor system 1 of the present embodiment, the host controller 42 is connected to the connector 18 of the network unit 10 via a cable, and a DC power source is connected to the connector 17. In each sensor unit, an optical fiber (not shown) is extended to a work monitoring position. The network unit 10 shown in FIG. 7 is provided with two connectors 18, and this shows an example in which the communication with the host controller 43 is a communication system premised on daisy chain connection, The connector 18 is connected to the host controller 43 or the other network unit 10 on the host side, and the other connector 18 is used while connected to the other network unit on the lower side or not connected. Needless to say, the present invention is not limited to the daisy chain connection but can be applied to other communication systems such as the multi-drop connection shown in FIGS.

  In the continuous sensor system 1 having such a configuration, a unique address is set for each sensor unit when a serial signal is transmitted. Address setting can be performed by a DIP switch or the like provided in each sensor unit, or address setting can be automatically performed by recognizing a connection state for each sensor unit.

  Now, when the continuous sensor system 1 is turned on, the network unit 10 requests each sensor unit to transmit the parameters set at that time. Each sensor unit transfers a set of parameters stored in the respective parameter memory 36 to the network unit 10 via the serial transmission line 41. The network unit 10 holds this data in the parameter memory 15.

  In the continuous sensor system 1, work control is performed as follows. When the timing signal is sent from the control unit 11 of the network unit 10 to the adjacent sensor unit 30-1, the timing signal is transmitted to the timing control unit 31a of the sensor unit 30-1.

  In the sensor unit 30-1, when the timing signal is transmitted to the timing control unit 31a, the control unit 31 causes the light emitting unit 32 to emit light, and the light receiving unit 33 can obtain different levels of received light signals depending on the presence or absence of a workpiece. The received light signal is binarized with a threshold set in the determination unit 31b. The sensor unit 30-1 outputs a discrimination signal to the outside through the output transistor Q1 and the output line 39. The determination signal and the amount of received light are held until the next timing signal is obtained.

  The timing controller 31a transmits the timing signal to the adjacent sensor unit from the connection terminal 38c after a predetermined time (for example, 10 μs) has elapsed since the timing signal was received. In this way, the timing signal delayed by a predetermined time in each sensor unit is transmitted to the downstream sensor unit in a bucket relay manner. Thereby, each sensor unit emits light with a delay of a predetermined time as it goes downstream, so that mutual interference between photoelectric sensors can be prevented.

  Next, normal data and parameter collection processing of the continuous sensor system 1 will be described with reference to the flowchart of FIG. 8 and the sequence diagram of FIG. First, as shown in the flowchart of FIG. 8, the network unit 10 periodically transmits a data transfer command (step S1).

  At this time, the network unit 10 attaches a common ID code to each sensor unit and sends a data transfer command to all sensor units via the serial transmission line 41. Here, the data may be only the determination signal or only the received light amount, or may be both the determination signal and the received light amount. Then, a response is obtained from each sensor unit via the serial transmission line 41. Although the reception timings are different, the obtained data itself is synchronized. Then, the received data from each sensor unit is temporarily held in the buffer (step S2). Then, values such as on / off information of received data and received light amount are held in the table memory 14 (step S3). FIG. 4A shows a memory map of the table memory 14 obtained in this way. The discrimination signal obtained from each sensor unit is in the first area 14-1, and the received light amount as sensor information is in the second area 14-2. Retained.

  Next, the process proceeds to a parameter update confirmation process, and the pointer i is set to 1 (step S4). Then, an update flag in the data of the sensor unit 30-i held in the buffer is extracted (step S5), and it is determined whether or not this flag is set (step S6). If the update flag is not set, the pointer i is incremented and the process returns to step S5 (step S7). If the update flag is set, the process proceeds to step S8 to request the sensor unit #i to transfer update parameters. At this time, only the changed parameter may be requested from the sensor unit #i, or all parameters may be requested. When the update parameter is transmitted from the requested sensor unit #i, the parameter of the sensor unit #i in the parameter memory 15 is updated in step S9. Then, it is determined whether i = 16, that is, the final sensor unit (step S10), and if it is not the final sensor unit, the process returns to step S7 and the same processing is repeated. If it is the last sensor unit, the process returns to step S1, and the network unit 10 sends the data transfer command again and performs the same processing.

  The sequence diagram shown in FIG. 9 shows a case where the sensor unit 30-3 updates the parameters, and then the sensor unit 30-1 updates the parameters.

  By doing this, if there is no parameter change in each sensor unit, the processing of steps S1 to S7 can be performed at high speed. If the parameter is updated, the parameter transfer can be requested only for the updated sensor unit and the parameter in the parameter memory 15 can be updated. Accordingly, the communication load on the serial transmission line 41 is reduced, and the latest parameters can always be held in the parameter memory 15 of the network unit 10.

  Next, the operation of each sensor unit will be described with reference to the sequence diagram of FIG. If there is a data transfer command, each sensor unit sends the requested data, that is, data such as discrimination information and received light amount, and an update flag to the network unit 10. If there is no parameter change, the update flag is off. However, when the user changes a parameter such as a threshold value using the operation unit 35, an update flag is set. Next, if there is a data transfer command, an on-state update flag is transmitted together with the data. In this way, since there is a request for an update parameter from the network unit 10, the parameter held in the parameter memory 36 is sent to the network unit 10. After sending the parameters, the update flag is turned off. In this way, the latest parameters can be held in the network unit 10 with a minimum increase in communication traffic.

  On the other hand, the network unit 10 reads out these from the table memory 14 in response to a discrimination signal of each sensor unit and an inquiry of the amount of received light from the host controller 42 and transmits them to the host controller 42 via the host IF 11a and the connector 18. . If there is a parameter request, the parameter is read from the parameter memory 15 and transmitted to the host controller 42 in the same manner. The host control device 42 can perform necessary processing using the determination signal, the amount of received light, and the parameter information.

(Second Embodiment)
Next, a continuous sensor system according to a second embodiment of the present invention will be described. The same parts as those of the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted. The continuous sensor system of this embodiment is configured by connecting at least one, here 16 sensor units 70-1 to 70-16 in series to a network unit 60 as shown in FIG. In addition to the serial transmission line 41, a parallel transmission line 44 is provided between the network unit 60 and the sensor units 70-1 to 70-16. In this way, the discrimination signal can be transmitted to the network unit 60 in real time using the parallel transmission line 44. The parallel transmission line 44 is connected to one signal line from each sensor unit, and is formed of at least 16 lines.

  Next, the network unit 60 of the present embodiment will be described with reference to FIG. The control unit 61 receives the determination signal transmitted from the parallel transmission line 44 in addition to the function of the control unit 11 of the first embodiment, updates the first area of the table memory 14 and holds it. Accordingly, it has a function of outputting to the host control device 42. The output determination receiving unit 11 c of the control unit 61 receives the determination signal of each sensor unit obtained from the parallel transmission line 44 and holds it in the table memory 14. In addition to the connection terminals 66a to 66e having the same function as the connection terminals 16a to 16e of the connector 16 of the first embodiment described above, the connector 66 includes 16 pieces connected to the downstream side of the parallel transmission line 44. Connection terminals 66f to 66u are provided.

  Also in this embodiment, sixteen sensor units 70-1 to 70-16 are connected to the network unit 60. However, since each sensor unit has the same configuration, the sensor unit 70-1 is based on the drawings. explain. FIG. 13 shows the sensor unit 70-1. The connector 77 has 16 connections connected to the upstream side of the parallel transmission line 44 in addition to the connection terminals 77a to 77e having the same functions as the connection terminals 37a to 37e of the connector 37 of the first embodiment. Terminals 77f to 77u are provided. The connection terminal 77f located at the end of the connection terminals 77f to 77u is connected to the collector of the output transistor Q2.

  On the other hand, the connector 78 has 16 connection terminals 78f connected to the downstream side of the parallel transmission line 44 in addition to the connection terminals 78a to 78e having the same functions as the connection terminals 38a to 38e of the first embodiment. ~ 78u. The connection terminal 78 f of the connector 78 is connected to the connection terminal 77 g of the connector 77, and the connection terminal 78 g of the connector 78 is connected to the connection terminal 77 h of the connector 77. Similarly, the connection terminal 78 t of the connector 78 is connected to the connection terminal 77 u of the connector 77. Thus, the connection terminals are shifted one by one between the downstream side parallel connection part and the upstream side parallel connection part, and these constitute a parallel transmission line 44.

  In this embodiment, each sensor unit detects a workpiece and transmits a discrimination signal to the network unit 60 independently via the parallel transmission line 44. On the other hand, the network unit 60 holds the discrimination signal transferred through the parallel transmission line 44 in the first area 14-1 of the table memory 14. In this embodiment, if the discrimination signal in the first area 14-1 of the table memory 14 is transferred to the host device in response to a request from the host controller, the discrimination information can be transmitted at a higher speed.

  The current discrimination signal obtained from the parallel transmission line 44 is temporarily held in the first area 14-1 of the table memory 14, but is directly transmitted to the host controller 42 as a parallel signal. Also good. In this case, the discrimination signal of each sensor unit at the present time can be transmitted to the host controller 42 in real time.

  In the above-described continuous sensor system of each embodiment, the sensor unit is a transmissive photoelectric sensor unit, but other types of sensor units such as a reflective photoelectric sensor unit and a proximity sensor unit may be used. The present invention can be applied to various sensor units that output a discrimination signal based on a detection signal.

  In each of the embodiments, 16 sensor units are connected to the network unit. However, any number of sensor units can be connected to the network unit 10 to configure a continuous sensor system.

  In this embodiment, when the sensor unit is connected to the network unit, the sensor unit is physically connected and electrically connected, but the physical connection and the connection on the signal are disconnected. May be. For example, several sensor units may be connected and connected to other sensor units by signal lines.

  The present invention relates to a continuous sensor system for monitoring the state of an object to be detected and a network unit and a sensor unit used in this system, because the communication load of serial transmission can be reduced and the parameters of each sensor unit can be updated. Therefore, it can be suitably used for a continuous sensor system that processes a workpiece in the above.

DESCRIPTION OF SYMBOLS 1 Consecutive sensor system 10, 60 Network unit 11, 31, 61 Control part 11a Higher level interface 11b Serial communication part 11c Output determination receiving part 14 Table memory 15, 36 Parameter memory 16, 17, 18, 37, 38, 67, 77, 78 Connectors 30-1 to 30-16, 70-1 to 70-16 Sensor unit 31a Timing control unit 31b Judgment unit 31c Serial communication unit 32 Light emitting unit 33 Light receiving unit 41 Serial transmission line 42 Host control device 43 Fieldbus 44 Parallel transmission line

Claims (9)

A continuous sensor system comprising a network unit connected to a host controller and at least one sensor unit, wherein the network unit is connected to any one of the sensor units and the sensor units. ,
Each sensor unit is
A sensor unit that outputs a detection signal according to a physical quantity detected from a detection target;
An operation unit for setting a parameter including a threshold for determination by the determination unit;
A parameter memory that holds a parameter set by the operation unit and an update flag indicating whether or not the parameter is updated;
When the detection signal obtained from the sensor unit is discriminated according to a threshold value, an update flag is set when a parameter is updated from the operation unit, and at least one of the discrimination signal and the detection signal of the sensor unit is sent A control unit for simultaneously transmitting an update flag to the network unit;
Connection means for connecting to any of the adjacent network unit and sensor unit;
Serial transmission means for transmitting and receiving a serial signal formed by a plurality of bits of signal,
The network unit is
Connection means for connecting to any one of the adjacent sensor units;
Serial transmission means for serially transmitting and receiving serial signals formed of a plurality of bits including the sensor unit discrimination signal;
A parameter memory for holding the parameters of each sensor unit;
A control unit that requests transmission of the changed parameter to the sensor unit that has transmitted the data with the update flag set when the parameter update flag is set among the data received via the serial communication means And a continuous sensor system.   2. The continuous sensor system according to claim 1, wherein the control unit of the network unit collects a parameter set in each sensor unit when the power is turned on and stores the parameter in the parameter memory.   2. The continuous sensor system according to claim 1, wherein each of the sensor units has a parallel signal line for transmitting a discrimination signal output from the control unit to the network unit in parallel. The network unit has a table memory for holding a discrimination signal sent from each sensor unit,
4. The continuous sensor system according to claim 3, wherein the control unit of the network unit detects the determination signal generated by the control unit of the sensor unit based on a signal change of a parallel signal line and updates the table memory. A network unit connected to a host controller and at least one sensor unit, and used in a continuous sensor system configured by connecting the network unit, any one of the sensor units, and the sensor units. A network unit,
Connection means for connecting to any one of the adjacent sensor units;
Serial transmission means for serially transmitting and receiving serial signals formed of a plurality of bits including the sensor unit discrimination signal;
A parameter memory for holding the parameters of each sensor unit;
A control unit that requests transmission of the changed parameter to the sensor unit that has transmitted the data with the update flag set when the parameter update flag is set among the data received via the serial communication means And a network unit.   The network unit according to claim 5, wherein the control unit collects parameters set in the sensor units when power is turned on and stores the parameters in the parameter memory.   The network unit according to claim 5, wherein each of the sensor units has a parallel signal line for transmitting a determination signal output from the control unit to the network unit in parallel. The network unit has a table memory for holding a discrimination signal sent from each sensor unit,
The network unit according to claim 7, wherein the control unit detects the determination signal generated by the control unit of the sensor unit based on a signal change of a parallel signal line and updates the table memory. A network unit connected to a host controller and at least one sensor unit, and used in a continuous sensor system configured by connecting the network unit, any one of the sensor units, and the sensor units. A sensor unit,
A sensor unit that outputs a detection signal according to a physical quantity detected from a detection target;
An operation unit for setting a parameter including a threshold for determination by the determination unit;
A parameter memory that holds a parameter set by the operation unit and an update flag indicating whether or not the parameter is updated;
When the detection signal obtained from the sensor unit is discriminated according to a threshold value, an update flag is set when a parameter is updated from the operation unit, and at least one of the discrimination signal and the detection signal of the sensor unit is sent A control unit for simultaneously transmitting an update flag to the network unit;
Connection means for connecting to any of the adjacent network unit and sensor unit;
And a serial transmission means for transmitting and receiving a serial signal formed of a plurality of bits.

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